WM8985 Datasheet, PDF (78/118 Pages) Wolfson Microelectronics plc – Multimedia CODEC With Class D Headphone and Line Out

WM8985
Pre-Production
REGISTER
ADDRESS
R6 (06h)
Clock
Generation
Control
BIT
LABEL
0
MS
4:2 BCLKDIV
7:5 MCLKDIV
8
CLKSEL
Table 44 Clock Control
DEFAULT
DESCRIPTION
0
Sets the chip to be master over LRC
and BCLK
0 = BCLK and LRC clock are inputs
1 = BCLK and LRC clock are outputs
generated by the WM8985 (MASTER)
000
Configures the BCLK output frequency,
for use when the chip is master over
BCLK.
000 = divide by 1 (BCLK=SYSCLK)
001 = divide by 2 (BCLK=SYSCLK/2)
010 = divide by 4 (BCLK=SYSCLK/4)
011 = divide by 8 (BCLK=SYSCLK/8)
100 = divide by 16 (BCLK=SYSCLK/16)
101 = divide by 32 (BCLK=SYSCLK/32)
110 = reserved
111 = reserved
010
Sets the scaling for SYSCLK clock
output (under control of CLKSEL)
000 = divide by 1 (LRC=SYSCLK/128)
001 = divide by 1.5 (LRC=SYSCLK/192)
010 = divide by 2 (LRC=SYSCLK/256)
011 = divide by 3 (LRC=SYSCLK/384)
100 = divide by 4 (LRC=SYSCLK/512)
101 = divide by 6 (LRC=SYSCLK/768)
110 = divide by 8 (LRC=SYSCLK/1024)
111 = divide by 12 (LRC=SYSCLK/1536)
1
Controls the source of the clock for all
internal operation:
0 = MCLK
1 = PLL output
AUDIO SAMPLE RATES
The WM8985 ADC high pass filter, ALC and DAC limiter characteristics are sample rate dependent.
SR should be set to the correct sample rate or the closest value if the actual sample rate is not
available.
If a sample rate that is not explicitly supported by the SR register settings is required then the
closest SR value to that sample rate should be chosen. The filter characteristics and the ALC attack
decay and hold times will scale appropriately.
REGISTER
ADDRESS
R7 (07h)
Additional
Control
BIT
LABEL
3:1 SR
Table 45 Sample Rate Control
DEFAULT
DESCRIPTION
000
Approximate sample rate (configures the
coefficients for the internal digital filters):
000 = 48kHz
001 = 32kHz
010 = 24kHz
011 = 16kHz
100 = 12kHz
101 = 8kHz
110-111 = reserved
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PP, Rev 3.4, October 2006
78